The upgrade is flagging PHP 5.5 already.
Yes, that’s correct (check the link on the end of the admin message). You should get only a green warning, because maintenance fixes ended on 10 July (10 days ago). You won’t get a red warning until 10th July next year so its perfectly safe until then.
and then brought over my Xenea theme images I like.
Not sure what they are, but if they are referred to in either the xenea style.css or theme.php files then you should read Customising themes. Put your preferred images in their own folder (in the same place, but not the themes /images/ folder), then create new references for them in a mystyle.css file by copying the standard references and modifying them for your new location. That way you will never need to move them again as future updates won’t touch those files.